Rotor control mechanism

ABSTRACT

A compact and unobtrusive rotor control mechanism is presented that provides collective and cyclic pitch change to both rotors of a coaxial rotor system as well as a differential collective pitch change to one or both rotors simultaneously.

The present application is a non-provisional of U.S. Provisional Patent Application Ser. No. 62/854,443, titled “Rotor Control Mechanism”, filed May 30, 2019, which is incorporated herein as if set out in full.

BACKGROUND

Traditional single rotor helicopters use simple, 3-input “swashplates,” such as the one depicted in Figure. These 3-input swashplates transmit inputs from the pilot to the rotor system in the form of collective pitch change (all blades being affected equally) and cyclic pitch change (each blade being affected uniquely in proportion to the tilt angle and azimuth of the swashplate). Helicopters with coaxial rotors employ a separate system of one type or another to impart a “differential collective” pitch change which affects the upper and lower rotors differently. These devices are typically heavy and cumbersome, such as the one depicted in FIG. 2. This adds unwanted weight, drag, and overall air vehicle height. What is needed is a multi-input compound swashplate assembly that is compact and unobtrusive.

SUMMARY

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary, and the foregoing Background, is not intended to identify key aspects or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use as an aid in determining the scope of the claimed subject matter.

The present disclosure provides a rotor control system for a rotor aircraft. In various embodiments, the system is provided as a compound swashplate assembly, including a first swashplate assembly and a second swashplate assembly. The first and second swashplate assemblies each include a non-rotating ring and a rotating ring coupled to one another by rotation bearings that allow the rotating ring to rotate with a transmission mast. In some embodiments, the non-rotating rings and rotating rings of the swash plate assemblies are joined to one another by a sliding journal, which allows the non-rotating ring and rotating ring to rise and fall perpendicular to the rotation bearings while remaining parallel to each other, without relative rotation.

In particular embodiments, the first rotating ring and second rotating ring each rise and fall along with their respective first non-rotating ring and second non rotating ring. The first rotating ring and second rotating ring may be coupled with one another to permit differential rise and fall of the first rotating ring and second rotating ring, in a manner that provides independent control of the upper and lower rotor collective pitch.

In various embodiments, an output of the first rotating ring is transmitted via linkages directly to pitch horns of a lower rotor. In such embodiments, an output of the second rotating ring may be transmitted via linkages to an upper swashplate assembly, whereby the upper swashplate reverses the direction of rotation to match an upper rotor. An output of the upper swashplate may also be transmitted via linkages directly to pitch horns of the upper rotor.

These and other aspects of the present system and method will be apparent after consideration of the Detailed Description and Figures herein. It is to be understood, however, that the scope of the invention shall be determined by the claims as issued and not by whether given subject matter addresses any or all issues noted in the Background or includes any features or aspects recited in this Summary.

DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention, including the preferred embodiment, are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

FIG. 1 depicts a perspective view of prior art, 3-input swashplate assembly.

FIG. 2 depicts an isometric view of a prior art rotor control assembly on a coaxial rotor helicopter that incorporates the use of a differential collective lever, an upper swashplate, and a lower swashplate.

FIG. 3 depicts a partial, elevation view of one embodiment of a compound swashplate assembly of the present technology.

FIG. 4 depicts isometric views of embodiments of non-rotating rings that can be used with the compound swashplate assembly of the present technology.

FIG. 5 depicts isometric views of embodiments of individual swashplate assemblies that can be used with the compound swashplate assembly of the present technology.

DETAILED DESCRIPTION

Embodiments are described more fully below with reference to the accompanying figures, which form a part hereof and show, by way of illustration, specific exemplary embodiments. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. However, embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. The following detailed description is, therefore, not to be taken in a limiting sense.

With reference to FIGS. 3-5, a novel rotor control for rotor aircraft is presented as embodiments of a compound swashplate assembly 10. The compound swashplate assembly 10 incorporates the use of, a first swashplate assembly 12 and a second swashplate assembly 14, contained within a single compound swashplate assembly 10. The first swashplate assembly includes a first non-rotating ring 16 and a first rotating ring 18 joined to one another by rotation bearings 20 that allow the first rotating ring 18 to rotate with a transmission mast of the aircraft. In various embodiments, the second swashplate assembly 14 is structured similarly to the first swashplate assembly 12, having a second non-rotating ring 22 and a second rotating ring 24 joined to one another by rotation bearings 26 that allow the second rotating ring 24 to rotate with the transmission mast.

In various embodiments of the present technology, the first non-rotating ring 16 and first rotating ring 18 of the first swash plate assembly 12 are joined to one another by a sliding journal, which may include one or more of a first sliding spline 18, partial spline, keyway, or guide rod(s) to allow the first non-rotating ring 16 and first rotating ring 18 to rise and fall perpendicular to the aforementioned rotation bearings 20 while remaining parallel to each other and without relative rotation. In such embodiments, the second swashplate assembly may be configured similarly to the first swashplate assembly 12. For example, the second non-rotating ring 22 and first rotating ring 24 may be joined to one another by a sliding journal that may include one or more of a second sliding spline 28, partial spline, keyway, or guide rod(s) to allow the second non-rotating ring 22 and first rotating ring 24 to rise and fall perpendicular to the rotation bearings 26 while remaining parallel to each other, without relative rotation.

With reference the embodiment depicted in FIG. 3, four actuation devices 30 are grounded to an airframe/other nonrotating structure 32 of the aircraft. The actuating devices 30 are coupled to the first non-rotating ring 16 and second non-rotating ring 22 of the compound swash plate assembly 10. In at least one embodiment, two of the actuation devices 30, arranged approximately 180° apart from one another, are attached to the first nonrotating ring 16 and the other two actuation devices 30, approximately 180° apart from one another and approximately 90° apart from the first two actuation devices 30, are attached to the second non-rotating ring 22. In an alternate embodiment three actuation devices 30, approximately equally spaced around the azimuth attached to the first non-rotating ring 16 and a fourth actuation device 30 attached to the second non-rotating ring 22 and grounded to either the airframe/other nonrotating structure 32 of the aircraft or the other non-rotating ring.

As further depicted in the exemplary embodiment, the first rotating ring 18 and second rotating ring 24 of the compound swash plate assembly 10 each rise and fall along with their respective first non-rotating ring 16 or second non rotating ring 22. Each is driven by its own drive link/lever arrangement 34 that is coupled with the transmission mast so they are always in synch with each other around the azimuth. It is this differential rise and fall of the first rotating ring 18 and second rotating ring 24 that allows independent control of the upper and lower rotor collective pitch.

In various embodiments of the present technology, as depicted in FIG. 3, the output of the first rotating ring 18 is transmitted via linkages 36 directly to pitch horns of a lower rotor. The output of the second rotating ring 24 is transmitted via linkages 38 to the upper swashplate assembly. The upper swashplate reverses the direction of rotation to match the upper rotor. The output of the upper swashplate is transmitted via linkages 40 directly to the pitch horns of the upper rotor.

Embodiments of the present technology do not require secondary system of links, levers, actuators, etc. to change differential collective pitch.

Although the technology been described in language that is specific to certain structures, materials, and methodological steps, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific structures, materials, and/or steps described. Rather, the specific aspects and steps are described as forms of implementing the claimed invention. Since many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. Unless otherwise indicated, all numbers or expressions, such as those expressing dimensions, physical characteristics, etc. used in the specification (other than the claims) are understood as modified in all instances by the term “approximately.” At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter recited in the specification or claims which is modified by the term “approximately” should at least be construed in light of the number of recited significant digits and by applying ordinary rounding techniques. Moreover, all ranges disclosed herein are to be understood to encompass and provide support for claims that recite any and all subranges or any and all individual values subsumed therein. For example, a stated range of 1 to 10 should be considered to include and provide support for claims that recite any and all subranges or individual values that are between and/or inclusive of the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less (e.g., 5.5 to 10, 2.34 to 3.56, and so forth) or any values from 1 to 10 (e.g., 3, 5.8, 9.9994, and so forth). 

What is claimed is:
 1. A rotor control system for an aircraft, the system comprising: a compound swashplate assembly, including a first swashplate assembly and a second swashplate assembly; the first swashplate assembly including a first non-rotating ring and a first rotating ring coupled to one another by rotation bearings that allow the first rotating ring to rotate with a transmission mast; and the second swashplate assembly including a second non-rotating ring and a second rotating ring joined to one another by rotation bearings that allow the second rotating ring to rotate with the transmission mast.
 2. The rotor control system of claim 1 wherein: the first non-rotating ring and first rotating ring of the first swash plate assembly are joined to one another by a sliding journal, which allows the first non-rotating ring and first rotating ring to rise and fall perpendicular to the rotation bearings while remaining parallel to each other, without relative rotation.
 3. The rotor control system of claim 2 wherein: the second non-rotating ring and second rotating ring of the second swash plate assembly are joined to one another by a sliding journal, which allows the second non-rotating ring and second rotating ring to rise and fall perpendicular to the rotation bearings while remaining parallel to each other, without relative rotation.
 4. The rotor control system of claim 1 further comprising: a plurality of actuation devices couple a nonrotating structure of the aircraft with the first non-rotating ring and the second non-rotating ring.
 5. The rotor control system of claim 4 wherein: a first pair of the actuation devices are arranged approximately 180° apart from one another and are attached to the first nonrotating ring; and a second pair of the actuation devices, approximately 180° apart from one another and approximately 90° apart from the first pair of actuation devices, are attached to the second non-rotating ring.
 6. The rotor control system of claim 4 wherein: three of the plurality of actuation devices are approximately equally spaced around an azimuth attached to the first non-rotating ring and a fourth actuation device is attached to the second non-rotating ring and grounded to the nonrotating structure of the aircraft.
 6. The rotor control system of claim 1 wherein: the first rotating ring and second rotating ring each rise and fall along with their respective first non-rotating ring and second non rotating ring.
 7. The rotor control system of claim 6 wherein: the first rotating ring and second rotating ring are each driven by a drive link that is coupled with the transmission mast so that the first rotating ring and second rotating ring are in synch with one other around an azimuth. It is this differential rise and fall of the first rotating ring and second rotating ring that allows independent control of the upper and lower rotor collective pitch.
 8. The rotor control system of claim 1 wherein: the first rotating ring and second rotating ring are coupled with one another to permit differential rise and fall of the first rotating ring and second rotating ring, in a manner that provides independent control of the upper and lower rotor collective pitch.
 9. The rotor control system of claim 1 wherein: an output of the first rotating ring is transmitted via linkages directly to pitch horns of a lower rotor.
 10. The rotor control system of claim 9 wherein: an output of the second rotating ring is transmitted via linkages to an upper swashplate assembly, whereby the upper swashplate reverses the direction of rotation to match an upper rotor.
 11. The rotor control system of claim 10 wherein: an output of the upper swashplate is transmitted via linkages directly to pitch horns of the upper rotor. 